In a manufacturing process such as cutting and assembling an LCD, and in an assembly process of an integrated machine of an electronic apparatus, a single-layer glass crack, that is, a microcrack, on an LCD may be caused by a problem in assembly technology, assembly device, or the like. In the prior art, microcrack detection is performed by using visual inspection or microscopic examination. However, missed detection of a blind crack is prone to occur in the visual inspection, and because a view in a case of the microscopic examination is excessively small, and a detected area cannot completely cover all marginal areas of an entire piece of glass, missed detection is also most likely to occur; in addition, whether the visual inspection or the microscopic examination is used, an electronic product needs to be disassembled, and testing is performed on an LCD after the LCD is detached, which is a complex testing process.